Various forms of open-heart surgery have been practiced for a number of years. Open-heart surgery normally requires the use of a system for the extracorporeal circulation of fluids through a number of fluid circuits. For example, one circuit is used to assume the cardiopulmonary functions of the patient by bypassing the heart and lungs. In this circuit, a catheter receives blood from a major vessel entering the heart and directs the blood through a venous line to a blood reservoir. An arterial pump is used to pump blood from the reservoir through an oxygenation device such as a membrane or bubble oxygenator and through an arterial line and another catheter into a major vessel exiting the heart. This pumping and oxygenation function temporarily replaces or supplements the pumping and oxygenation function of the heart and lungs. The arterial pump circuit may include other devices such as bubble detectors to guard against bubbles entering the bloodstream; temperature sensors and heat exchangers to monitor and control the temperature of the circulated blood; pressure transducers to monitor the pressure in the extracorporeal circuit; a timer; cardiac index monitor; and devices to monitor blood characteristics such as the hemoglobin oxygen saturation level, hematocrit, pH, and blood gasses.
The arterial pump is typically a peristaltic pump in which a set of rollers are mounted on a rotor which rotates through a raceway. A flexible tube is mounted in the raceway between the raceway and the rollers. The rotation of the rotor moves the rollers through the raceway to successively occlude the flexible tube, thereby driving the fluid in the tube through the tube in the direction of the moving rollers. Rotary peristaltic pumps are attractive for pumping blood or other body fluids because they are relatively reliable and simple to operate, and they are sanitary since they do not directly contact the fluid being pumped. Centrifugal pumps or other types of pumps may also be used. Regardless of the type of pump that is used, it may be operated in a steady and continuous manner or in a pulsatile manner to mimic the beating of the heart.
Another potential circuit in the extracorporeal circulation system involves a cardioplegia pump. Most types of common surgery on the heart necessitate a temporary reduction or discontinuance in the beating of the heart in a manner that will not cause damage to the myocardium. This is accomplished by using a cardioplegia pump to pump a cardioplegia solution into the coronary arterial network for distribution throughout the myocardium. The solution drains through the coronary sinus, and can be drawn out of the chest cavity and discarded or directed toward the arterial pump for mixing with systemic blood.
The cardioplegia pump which infuses the myocardium arterial network with cardioplegia solution is typically somewhat similar in design to the arterial pump which bypasses the heart and lungs; it is commonly a peristaltic pump in which a set of rollers mounted on a rotating rotor successively occlude a flexible tube to drive the solution therethrough. As in the case of the arterial pump, the cardioplegia circuit may include other devices such as pressure transducers to monitor the solution pressure to keep it within an acceptable range; an air detector; a timer; and a temperature sensor and heat exchanger to monitor and control the temperature of the cardioplegia solution. In addition, the cardioplegia circuit may include a device for controlling and recording the total volume of cardioplegia solution that is pumped.
Typical extracorporeal systems for use in openheart surgery may contain one or more additional circuits, beyond the arterial circuit and cardioplegia circuit. For example, the system may include one or more auxiliary pumps to draw free blood and cardioplegia fluid from the patient and to add it to the blood reservoir to be mixed with systemic blood to be pumped by the arterial pump. Although uncommon, the system in some configurations may include a venous pump separate from the arterial pump to draw venous blood out of the patient and direct it to a reservoir where the arterial pump can pump it through an oxygenator and heat exchanger. One or more additional pumps may be included in the system for use as back-up pumps in the event of a failure of a primary pump.
Existing systems for extracorporeal circulation are commonly mounted on a wheeled console for convenient storage, transport and use. The typical mounting configuration includes a row of discrete perfusion assemblies, each perfusion assembly including a pump for use as an arterial pump, cardioplegia pump, auxiliary pump, back-up pump, or any other pump needed for the chosen system configuration. Each perfusion assembly may also include a pump control panel. The pump houses the actual pumping elements such as a rotor with a set of rollers to engage the flexible tubing through which the pumped fluid flows and a raceway to hold the flexible tubing in place. It also contains the pump motor and other mechanical components. The pump control panel may include controls such as power switches, speed adjustments and indicators, and forward and reverse controls.
The wheeled console commonly has a number of accessories and a structure for attachment of the accessories. The structure may include one or more vertical poles or "masts," a horizontal crossbar connecting one or more of the masts, and sets of hooks and brackets for hanging or attaching fluid reservoirs, accessory instrumentation, writing surfaces and any other desired elements such as bubble detectors, temperature sensor readouts and other devices mentioned previously.
In the prior art, the pump control panel for each perfusion assembly does not always include all the instrumentation associated with that perfusion assembly and the fluid being pumped by that perfusion assembly. Instead, the configuration generally used in the prior art involves positioning some of the instrumentation on the pump control panel and positioning other instrumentation on a separate module. For example, in one common configuration instrumentation such as speed control, delivery rate readout, forward and reverse, and certain other elements are positioned on the pump control panel for each pump, but other instrumentation such as pulsatile control, pressure detection, temperature readouts and certain other elements are positioned at a remote location. The remote location is often a central CRT, a conglomeration of modules or a touchscreen display module, that is used to control and display certain functions for all of the perfusion assemblies used in the system. This centralized display module is usually the source of more information and controls than can actually be displayed and operated at one time; therefore, the perfusionist must affirmatively request the information and controls that are to be displayed and operated from time to time.
The centralized display module is often mounted on one of the vertical masts attached to the console or to a horizontal crossbar that extends between two masts. It may share the masts and crossbar with pressure sensors, an oxygenator and reservoir, air bubble detectors, heat exchangers, individual instruments, and other accessories, all of which are suspended or attached to the structure by hooks and brackets.